Projectile

ABSTRACT

A system for propelling an air-driven projectile from an air gun includes an air gun with an elongate bore and a source of compressed air in fluid communication with the elongate bore. An elongate projectile is disposed within the bore of the air gun, the elongate projectile having an outer diameter that is less than an inner diameter of the elongate bore, wherein the elongate projectile has a length that is at least substantially equivalent to a length of the elongate bore of the air gun. The elongate projectile has a butt on a proximal end of the projectile and a tip on a distal end of the projectile, wherein the butt comprises an outer diameter that is greater than an outer diameter of the elongate projectile and less than the inner diameter of the elongate bore.

PRIORITY CLAIM

This application claims priority to U.S. Provisional Patent Application 62/018,165 filed on Jun. 27, 2014 entitled “Improved Air Gun Dart” which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This invention relates generally to the projectiles. Specifically, it relates to an improved projectile for use in an air gun or bow.

BRIEF DESCRIPTION OF THE FIGURES

To further clarify the above and other aspects of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The drawings are not drawn to scale. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a perspective view of an air elongate projectile in accordance with one aspect of the technology;

FIG. 2a is a perspective view of a stabilizer in accordance with one aspect of the technology;

FIG. 2b is a cross-sectional side view of the stabilizer of FIG. 2 a;

FIG. 2c is a top view of the stabilizer of FIG. 2 a;

FIG. 2d is a bottom view of the stabilizer of FIG. 2 a;

FIG. 3a is a perspective view of a butt in accordance with one aspect of the technology;

FIG. 3b is a cross-sectional side view of the butt shown in FIG. 3 a;

FIG. 3c is a top view of the butt shown in FIG. 3 a;

FIG. 4a is a perspective view of a tip in accordance with one aspect of the technology;

FIG. 4b is a cross-sectional side view of the tip shown in FIG. 4 a;

FIG. 4c is a top view of a tip in the tip shown in FIG. 4 a;

FIG. 5a is a perspective view of a butt in accordance with one aspect of the technology;

FIG. 5b is a cross-sectional side view of the butt shown in FIG. 5 a;

FIG. 5c is a top view of the butt shown in FIG. 5a ; and

FIG. 6 is a perspective view of a butt with an O-ring in accordance with one aspect of the technology.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

The following detailed description of exemplary embodiments of the invention makes reference to the accompanying drawings, which form a part hereof and in which are shown, by way of illustration, exemplary embodiments in which the technology may be practiced. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the technology may be made without departing from the spirit and scope of the present invention. Thus, the following more detailed description of the embodiments of the present technology is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the present technology, to set forth the best mode of operation of the technology, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the present invention is to be defined solely by the appended claims.

The following detailed description and exemplary embodiments of the invention will be best understood by reference to the accompanying drawings, wherein the elements and features of the invention are designated by numerals throughout.

The present technology in its various embodiments, some of which are depicted in the figures herein, can be broadly described as an improved projectile having a tip disposed about the end of a shaft and butt elements disposed about the rear end of the shaft. In one aspect, a stabilizer member is disposed apart from the butt element. However, in another aspect, the butt also comprises a stabilizer member. Broadly speaking, the technology resides in a shaft with a tip sized to be slightly larger than the diameter of a rifle bore so as to stop further downward movement of the elongate projectile shaft within the bore. A cylindrical butt is disposed about the rear end of the elongate projectile shaft having a front face that induces a predetermined amount of drag about the butt. A cylindrical stabilizer can be disposed forward of the butt and also has a front face that induces an amount of drag about the stabilizer. Advantageously, the enhanced drag about the front face of the butt/stabilizer functions to “center” the elongate projectile while in flight, increasing the ability of the elongate projectile to travel straight to its intended target. While an elongate air projectile for use in an air gun is specifically referenced herein, one of ordinary skill in the art will recognize that the technology can be used in connection with an arrow used in a traditional bow, compound bow, or other device that is capable of providing a force to the rear end of the projectile. The resulting projectile is more accurate over longer distances than traditional elongate projectiles (i.e., arrows and elongate projectiles) and is safer and quieter than conventional firearms.

The projectile disclosed herein may be used in connection with an air gun. An air gun is any variety of projectile weapon that propels projectiles by means of compressed air or other gas, in contrast to firearms which use a propellant charge. Air guns are used for hunting, pest control, recreational shooting (commonly known as plinking), and competitive sports, such as the Olympic 10 m Air Rifle and 10 m Air Pistol events. In one aspect of the technology, the elongate projectile is used in connection with an air gun having a rifled bore. Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its longitudinal axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy. Rifling is often described by its twist rate, which indicates the distance the rifling takes to complete one full revolution, such as a one inch turn in ten inches (1:10 inches), or a 1 millimeter turn in 254 mm (1:254 mm). A shorter distance indicates a “faster” twist, meaning that for a given velocity the projectile will be rotating at a higher spin rate. The combination of length, weight and shape of a projectile determines the twist rate needed to stabilize it—barrels intended for short, large-diameter projectiles like spherical lead balls require a very low twist rate, such as 1 turn in 48 inches (122 cm). Barrels intended for long, small-diameter bullets, such as the ultra-low-drag, 80-grain 0.223 inch bullets (5.2 g, 5.56 mm), use twist rates of 1 turn in 8 inches (20 cm) or faster.

In some cases, rifling will have twist rates that increase down the length of the barrel, called a gain twist or progressive twist. Long projectiles, such as the elongate projectiles described herein, are thought to require high twist rates and are recommended to be fired from a smoothbore barrel. Aspects of the technology described herein cure that deficiency.

Projectile shafts, including arrows, have various sizes and fletchings or vanes of different designs. These vanes are for the purpose of better stabilization to start the arrow or elongate projectile shaft spinning Spinning the arrow shaft is important for shaft stabilization for a number of reasons. The present technology introduces additional elements for shaft stabilization. When a standard arrow shaft is released from a bow, the arrow shaft bends around the bow staff. This is due to the arrow being forced from a standstill to full speed very quickly. This bending back and forth creates drag and decreases arrow speed. The presence of vanes and fletchings, while intended to assist in shaft spinning, also creates drag and decreases arrow speed. While shooting an arrow or an elongate projectile with fletchings or vanes in an environment with cross-winds, accuracy of the projectile is severely hampered. This is not to say that fletchings may not be used in the current invention. Rather, in certain aspects, fletchings are not used.

With specific reference now to the figures, FIGS. 1-6 disclose an elongate projectile 5 in accordance with one aspect of the technology. The elongate projectile 5 comprises a shaft 10 having a tip 20, a butt 30, and a stabilizer 50. In one aspect of the technology, the shaft 10 is made of a carbon fiber. However, it is understood that the shaft 10 may be constructed from aluminum, plastic, or any other material suitable for an elongate projectile. In accordance with one aspect of the technology, the tip 20 comprises a machined brass cylinder tapering in both the forward and rearward directions. The outer diameter of the tip 20 is sized larger than the inner diameter of the bore of a rifle. For example, if the bore of a rifle was 0.500 inches (i.e., 50 caliber), the maximum outer diameter of the tip 20 could be sized at 0.515 inches. In this manner, the tip 20 acts as a stop for insertion of the projectile into the bore of the rifle. The front end 21 of the tip 20 is tapered in order to maximize aerodynamics and reduce drag created from wind resistance. The rear end 22 of the tip 20 is also tapered. The tapering of the rear end 22 of the tip 20 functions to help center the tip 20 within the bore as the shaft 10 rests in the bore. In another aspect of the technology, the rear end 22 of the tip 20 is not tapered. Rather, it comprises a substantially flat face and an annular protrusion (or a plurality of at least three individual protrusions) that is collinear with the center of the bore and is intended to seat within the bore of the rifle and center the projectile 5 within the bore of the rifle. The inner diameter of the tip 20 is substantially similar to the outer diameter of the shaft 10 and is secured to the distal end of the shaft 10. In one aspect of the invention, the inner diameter of the tip 20 is substantially similar to the outer diameter of the shaft 10 near a rear opening 23 of the tip 20. The front opening 24 of the tip 20 has a diameter smaller than the shaft 10 to provide for a “seat” for the distal end of the shaft 10. In yet another aspect, the tip 20 comprises a plurality of three blades or points disposed about the exterior of the front end 21 of the tip 20. The front end 21 may be sized to fit within the bore of the rifle with the three blades or points acting to center the shaft 10 within the bore.

In one aspect of the technology, the tip 20 is removably secured to the shaft 10 so that a variety of different tips may be used on the same shaft. For example, the tip 20 may be replaced with a broad-head tip for hunting purposes, flat faced tips for target practice, or other tips used for other purposes. The tip 20 may be threaded onto the shaft 10, press-fit, or permanently secured by glue or some other method known in the art. In one aspect of the technology, the tip 20 is made of a dense, heavy material such as brass. The tip 20 is designed to be heavier than the remainder of the shaft 10, the stabilizer 50, and the butt 30. In this manner, the center of gravity of the elongate projectile 5 is balanced forward of the center 11 of the elongate projectile 5 which results in increased stabilization of the projectile 5 during travel through the air. While reference is made to a machined tip, it is understood that the tip 20 may be cast, molded or manufactured in a number of methods known in the art.

In one aspect of the technology, the butt 30 comprises a rigid cylinder having an annular groove (or channel) 31 disposed near the front end of the cylinder and circumscribing the cylinder. The semi-rigid cylinder has an outer diameter that is sized slightly smaller than the inner diameter of the bore of a rifle. In one aspect, the rear end of the butt 30 is tapered to assist in the placement of the projectile 5 into the bore of the rifle. The annular groove 31 is sized to receive one or more resilient O-rings 60 therein with the O-rings circumscribing the annular groove 31. When placed within the annular groove 31, the outer diameter of the O-ring is sized slightly larger than the inner diameter of the rifle bore. In this manner, the O-ring acts to seal the rifle bore to enable pressurized air from an air rifle to deliver a propulsive force to the elongate projectile 5. The O-ring also engages the riflings within the bore. As the elongate projectile 5 is propelled down the bore of the rifle, the riflings cause the elongate projectile 5 to rotate within the shaft 10. The spinning or rotation of the elongate projectile 5 within the bore increases the stabilization of the elongate projectile 5 while in flight. The lack of fletchings or vanes that are traditionally used to achieve spinning, results in a more stable flight path in any type of cross-wind. In other words, the flight path of arrows or elongate projectiles that have traditionally relied on fletchings or vanes to spin while in flight are negatively affected by a cross wind catching on the fletchings or vanes. The present technology eliminates that concern allowing the projectile 5 to fly straighter and longer distances.

With reference to FIGS. 5a through 6, in accordance with one aspect of the technology, the annular groove 31 is tapered such that a front end 38 of the annular groove 31 has a smaller diameter than a back end 39 of the annular groove 31. An O-ring (or other shaped sealing member) is placed in the groove 31 and is sized to fit around the smaller diameter of the front end of the annular groove 31. As the elongate projectile 5 is inserted into the bore of the rifle, the O-ring 60 a rides on the front end of the annular groove 31, the inside of the bore creating friction so that the O-ring 60 a resists placement into the bore. When a force is provided on the rear end of the butt 30 to propel the elongate projectile 5 out of the rifle, the O-ring 60 b resists movement based on frictional engagement with the inside of the bore of the rifle. As the elongate projectile 5 is propelled forward, the O-ring 60 b rides on the back end of the annular groove 31. Because the back end of the annular groove 31 has a diameter that is larger than the front end of the annular groove, the O-ring is stretched to match the diameter of the annular groove. In this manner, the outer diameter of the O-ring increases and creates increased frictional engagement with the inside of the bore. Advantageously, the increased frictional engagement increases the seal with the inside of the bore improving the efficiency of the air propulsion and improving the engagement with the riflings on the inside of the bore.

In accordance with one aspect of the technology, the O-ring is made of a resilient material such as rubber, nitrile, or polymeric materials. The butt 30 is made from an acetal resin such as Delrin® though it may be made from any suitable material, including, but without limitation, polymers, plastics, alloys and the like. The butt 30 may be molded, extruded, machined, or formed by any suitable method known in the art. The annular groove 31 is placed in the forward half of the cylindrical butt 30. The side surfaces 37 of the butt 30 act as a bearing surface to facilitate travel down the bore of the rifle as the elongate projectile 5.

In accordance with one aspect of the technology, the front face 34 of the butt 30 is substantially perpendicular to a longitudinal axis of the elongate projectile shaft 10. Drag (sometimes called air resistance or air friction) refers to the force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or a fluid and a solid surface. In the instant application, the interaction between the air and the elongate projectile 5 as the elongate projectile 5 moves in its flight path and the front face 34 of the butt 30 creates drag or frictional forces that act about the outer edge 35 of the front face 34 of the butt 30. While the drag has the negative effect of reducing the speed of the elongate projectile 5, the frictional forces are distributed evenly about the outer edge 35 of the front face 34 and act to stabilize the flight path of the elongate projectile 5.

In accordance with one aspect of the technology, the front face 34 of the butt 30 may be tapered. For example, the front face 34 may be linearly tapered outward at a forty-five degree angle. The tapering of the front face 34 decreases the drag on the butt 30 thereby increasing the speed of the elongate projectile 5, but decreasing the stabilization of the elongate projectile 5 while in flight. While a forty-five degree angle is specifically referenced, the angle of the taper may vary as suits a particular application, particularly with respect to the balancing between increased stability versus increased drag. For example, the front face 34 may vary from ninety degrees (not tapered) to twenty-five degrees (significantly tapered) with a preferred tapering of forty-five degrees. In another aspect, the front face 34 may taper outwardly in a non-linear fashion forming a curved outer surface. The front face 34 may also be linearly tapered inward (or non-linearly, i.e., concave) to increase the amount of drag on the elongate projectile 5 while in flight. The increase in drag increases the stability of the flight path of the elongate projectile 5 at the expense of reduced speed of the projectile 5. The rear end 36 of the butt 30 has a slight taper to facilitate placement of the butt 30 within the bore of a rifle. The inner diameter of the butt 30 is sized to receive an end of the shaft 10 therein. The butt 30 is secured to the shaft 10 permanently (e.g., glued, fused, etc.) or can be removably secured to replace the butt 30 if it becomes worn over time or if the user wishes to use the elongate projectile 5 in a different application (e.g., as a nocked arrow).

A stabilizer 50 is disposed along the shaft 10 of the elongate projectile 5. In one aspect of the technology, the stabilizer 50 is cylindrically shaped with an annular groove 51 disposed therein. The annular groove 51 functions similar to the groove 31 located within the butt 30. That is, it houses an O-ring intended to engage with the riflings of the bore of a rifle. The engagement of the O-rings with the riflings causes the shaft 10 to rotate or spin within the bore. The resulting spinning action increases the elongate projectile 5 stability during flight. Side surfaces 52 of the stabilizer 50 act as bearing surfaces to facilitate travel of the shaft 10 down the bore of the rifle and create the ultimate flight path of the elongate projectile 5. In one aspect of the technology, the stabilizer 50 is spaced a distance of at least five times the diameter of the bore from the butt 30. In other words, if the bore of a rifle intended to propel the elongate projectile 5 has an inner diameter of 0.50 inches, the distance between the front face 34 of the butt 30 and the rear face 53 of the stabilizer 50 is 2.5 inches. The stabilizer 50 may be placed a distance beyond five times the diameter of the bore away from the butt 30 depending on the size of the bore and the relative weight of the elongate projectile 5. For elongate projectiles that are relatively heavy, with a tip that is light (based on a desired use of the tip) the stabilizer 50 may be placed nearer the center 11 of the shaft 10 in an effort to balance the elongate projectile 5 to maximize projectile stability. In one aspect of the technology, the annular groove 51 is disposed in the front half of the stabilizer 50. However, in other aspects, the annular groove 51 is disposed in the middle of the stabilizer 50 or towards the rear end of the stabilizer 50.

As with the butt 30, the front face 54 of the stabilizer 50 is substantially perpendicular to a longitudinal axis of the shaft 10 of elongate projectile 5. Similar to the drag created on the front face 34 of the butt 30, as the elongate projectile 5 travels through the air, frictional forces from the air act equally about the outer edge 55 of the front face 54 creating a stabilizing force on the elongate projectile 5 in flight. In one aspect of the technology, the front face 54 may be tapered outward to reduce the drag about the front face 54. In another aspect, the front face 54 may be tapered inward or concave to increase the drag on the front face 54.

While specific reference is made herein to a cylindrical front face 54, it is understood that the front face 54 of the stabilizer 50 (as well as the front face 34 of the butt 30) may have designs placed thereon to optimize the ratio between drag and projectile speed. For example, the front face 54, may not be perfectly planar. Rather, it may have protrusions, indentations, or other designs associated therewith. In addition, other modifications may be made to optimize projectile spin as suits a particular application. For example, one or both of the tip 20 and the stabilizer 50 may be equipped with grooves disposed at an angle to the longitudinal axis of the elongate projectile 5 to induce spinning when the elongate projectile 5 is launched from a smooth bore barrel, cross-bow, or other apparatus that lacks riflings. In certain aspects of the technology, the butt 30 is configured to act as the stabilizer. This may be in addition to a stabilizer 50 disposed elsewhere about the shaft 10, and may include fletchings that act as conventional stabilizers. It may also include aspects without any additional stabilization means. 

1. A system for propelling an air-driven projectile from an air gun, comprising: the air gun comprising an elongate bore and a source of compressed air in fluid communication with the elongate bore; an elongate projectile disposed within the bore of the air gun, the elongate projectile having an outer diameter that is less than an inner diameter of the elongate bore; wherein the elongate projectile has a length that is at least substantially equivalent to a length of the elongate bore of the air gun; and wherein the elongate projectile comprises a butt on a proximal end of the projectile and a tip on a distal end of the projectile, wherein the butt comprises an outer diameter that is greater than an outer diameter of the elongate projectile and less than the inner diameter of the elongate bore.
 2. The system of claim 1, wherein the tip of the elongate projectile comprises an annular seal disposed about a rear end of the tip, the annular seal having an outer diameter that is greater than the inner diameter of the bore.
 3. The system of claim 2, wherein the annular seal comprises a tapered rear end.
 4. The system of claim 3, wherein the length of the elongate projectile is greater than the length of the bore of the air gun.
 5. The system of claim 2, wherein the body of the butt is sized to approximate the shape of a cylinder, a front end of the butt being tapered and a rear end of the butt being tapered.
 6. The system of claim 2, wherein the butt comprises an annular groove disposed about the body of the butt and circumscribing the butt.
 7. The system of claim 6, further comprising an O-ring disposed within the annular groove and circumscribing the annular groove.
 8. The system of claim 7, wherein an outer diameter of the O-ring is greater than the inner diameter of the bore of the air gun.
 9. The system of claim 7, further comprising a plurality of O-rings disposed within the annular groove.
 10. The system of claim 1, wherein the tip comprises at least three protrusions in contact with the bore of the air gun.
 11. A projectile, comprising: an elongate tubular member; a tip disposed about a distal end of the elongate tubular member; a butt disposed about a proximal end of the elongate tubular member, wherein the butt has an outer diameter that is greater than an outer diameter of the elongate tubular member and comprises a rear face having a diameter greater than the diameter of the elongate tubular member and wherein the butt comprises an annular tapered front face; an annular groove disposed about the butt, said annular groove circumscribing the butt; and an O-ring disposed within the annular groove, said O-ring circumscribing the annular groove.
 12. The projectile of claim 11, wherein the annular groove tapers from a front of the groove to a rear of the groove, the front of the annular groove having an outside diameter that is smaller than a rear of the annular groove.
 13. The projectile of claim 11, further comprising a plurality of O-rings disposed within the annular groove.
 14. The projectile of claim 12, wherein the O-ring, in an unbiased state, comprises an inner diameter that is substantially equivalent to the outer diameter of the front of the annular groove and an outer diameter that is substantially equivalent to the outer diameter of the butt.
 15. The projectile of claim 11, further comprising a cylindrical stabilizer member disposed apart from the butt and forward of the butt about the elongate projectile.
 16. A method of propelling a projectile from an air gun, comprising: placing a quantity of pressurized fluid into the air gun, the quantity of pressurized fluid in fluid communication with a bore of the air gun; placing an elongate projectile into the bore of the air gun, wherein said elongate projectile comprises a cylindrical butt disposed about a proximal end of the elongate projectile, the butt having a rear face with a diameter that is greater than a diameter of the elongate projectile, the butt comprising an annular groove circumscribing the butt and an O-ring disposed within and circumscribing the annular groove; releasing the pressurized fluid into the bore of the air gun propelling the elongate projectile from the bore of the air gun, wherein as the elongate projectile is propelled down the bore of the air gun, the O-ring frictionally engages riflings within the air gun causing the elongate projectile to rotate within the bore of the air gun.
 17. The method of claim 16, wherein the annular groove disposed within the butt is tapered from a front of the annular groove to a rear of the annular groove, the front of the annular groove having a diameter that is smaller than the rear of the annular groove.
 18. The method of claim 17, wherein when the projectile is placed within the bore of the air gun, the O-ring frictionally engages the bore of the air gun and is forced to the front of the annular groove.
 19. The method of claim 17, wherein when the projectile is propelled out of the bore of the air gun, the O-ring frictionally engages the bore of the air gun and is forced to the rear of the annular groove.
 20. The method of claim 19, wherein the O-ring expands as it is forced to the rear of the annular groove increasing the frictional engagement of the O-ring with the bore of the air gun. 